An EL element in a prior art EL display has been formed by laminating a transparent electrode layer, a luminescent layer, an insulation layer and a back electrode layer, and attaching electrode connecting portions which project respectively from the transparent electrode layer and the back electrode layer for applying an AC electric field between the transparent electrode layer and the back electrode layer. Flat cables and the like are connected to the electrode connecting portions to electrically connect the EL display with an external driving control circuit.
Further, as a prior art technology pertaining to wristwatches, there has been known an EL display in which a transparent electrode layer is connected with an electrode by an electrode connecting portion formed by extending the transparent electrode layer, and a back electrode layer is connected with an electrode by an electrode contact layer provided on the back of the back electrode layer, such as shown in U.S. Pat. No. 5,265,071. In this technology, the transparent electrode layer is rendered conductive with the electrode by winding the electrode connecting portion of the transparent electrode layer around the side of a frame and by screwing to the electrode of a circuit board provided on the back of the frame.
However, if the electrode connecting portion is formed so as to project toward the outside like the above-mentioned prior art technology, the luminescent area of the EL display is reduced because the electrode connecting portion is a non-luminescent area. Further, a cavity portion has to be provided on the side of a case corresponding to the projecting electrode connecting portion, thus requiring a complicated mold and increasing the cost. Moreover, because the electrode connecting portion is provided so as to project within a small area at an extremely limited specific position in order to minimize the non-luminescent area, there have been such problems that the connecting position at which the electrode connecting portion is connected with the driving circuit is naturally limited into a narrow range and a high precision positioning is required, thus increasing the cost of the assembly process.
U.S. Pat. No. 5,265,071 has had another problem, beside the above-mentioned problems, in that it requires high precision processing in narrow sections to provide screw holes, for example, on the electrode connecting portion, the frame and the circuit board to screw the electrode connecting portion of the transparent electrode layer.